Ring network protection method, network node and ring network

ABSTRACT

A ring network protection method, a network node and a ring network are provided. The ring network protection method includes: receiving, by a network node, a ring network protection switching request message sent by a node that detects a fault when the fault occurs in the ring network, where the ring network protection switching request message carries source and destination node information of the ring network protection switching request message; and determining a fault location according to the source and destination node information, selecting a protection tunnel according to the determined fault location, and switching services to the selected protection tunnel, where the selected protection tunnel is a link protection tunnel of a link between the network node and a source node, or a node protection tunnel of an intermediate node on a short way between the network node and the source node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2010/071812, filed on Apr. 16, 2010, which claims priority toChinese Patent Application No. 200910136240.3, filed with the ChinesePatent Office on Apr. 29, 2009 and entitled “RING NETWORK PROTECTIONMETHOD, NETWORK NODE AND RING NETWORK”, the contents of which are allincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to the field of communicationstechnologies, and in particular, to a ring network protection method, anetwork node and a ring network.

BACKGROUND OF THE INVENTION

In recent years, packet switching technology fast becomes popular andstarts to be used in a transport network of an operator. At present, aMultiple Protocol Label Switch (MPLS) network in the packet switchingtechnology usually uses a mesh topology structure, while the transportnetwork usually uses a ring topology structure due to its deploymentfeatures. A conventional transport network, for example, a SynchronizedDigital Hierarchy (SDH) network, mostly uses the ring topologynetworking, and implements fast protection switching of servicesaccording to the features of a ring network. In SDH times, theapplication and demand of the ring are rather common, as proved byactual deployment. After the transition of the transport network fromthe SDH to a packet switching network, since a fiber deployed in advancestill has a ring shape, the ring network technology of the packetswitching network still has a wide application prospect.

Currently, in the ring network, a link protection tunnel may beestablished for each link or a node protection tunnel may be establishedfor each node. However, when only the link protection tunnel isestablished, the node cannot be protected in the case of a node fault.When only the node protection tunnel is established, as shown in FIG. 1,for example, a node protection tunnel T is established for a node B,normal transmission of the services at the node B cannot be implementedwhen a fault occurs in the link between the nodes A and B.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a ring network protectionmethod, a network node and a network system, through which, a protectiontunnel can be correctly selected when a link fault or a node faultoccurs in the ring network, so as to ensure normal service transmission.

In view of this, an embodiment of the present invention provides a ringnetwork protection method, which includes:

receiving, by a network node, a ring network protection switchingrequest message sent by a node that detects a fault, when a fault occursin the ring network, where the ring network protection switching requestmessage carries source and destination node information of the ringnetwork protection switching request message; and

determining a fault location according to the source and destinationnode information, selecting a protection tunnel according to thedetermined fault location, and switching services to the selectedprotection tunnel, where the selected protection tunnel is a linkprotection tunnel between the network node and a source node, or a nodeprotection tunnel of an intermediate node on a short way between thenetwork node and the source node.

A ring network protection method is further provided, which includes:

when a fault occurs in a ring network, selecting, by a first node, aprotection tunnel according to a fault condition of a pre-establishedprotection tunnel switching services to the selected protection tunnel,sending a protection switching request message in the selectedprotection tunnel, and informing another end node of the selectedprotection tunnel to switch the services to the selected protectiontunnel.

A ring network protection method is further provided, which includes:

sending, by a first node, a protection switching request message on alink protection tunnel of a link between the first node and a secondnode, and a node protection tunnel of the second node respectively whena fault occurs in a ring network;

receiving a protection switching response message on the link protectiontunnel of the link between the first node and the second node, or thenode protection tunnel of the second node; and

switching services to the protection tunnel where the protectionswitching response message is received.

A network node is provided, where the network node is located in a ringnetwork, and includes:

a receiving unit, configured to receive a ring network protectionswitching request message, where the ring network protection switchingrequest message carries source and destination node information of thering network protection switching request message; and

a protection tunnel selection unit, configured to determine a faultlocation according to the source and destination node information, andselect a protection tunnel according to the determined fault location,where the selected protection tunnel is a link protection tunnel of alink between a source node and the network node, or a node protectiontunnel of an intermediate node on a short way between the source nodeand the network node.

A network node is provided, where the network node is located in a ringnetwork, and includes:

a selection unit, configured to select a protection tunnel according toa fault condition of a pre-established protection tunnel;

a switching unit, configured to switch services to the selectedprotection tunnel; and

a sending unit, configured to send a protection switching requestmessage on the selected protection tunnel.

A network node is provided, which includes:

a sending unit, configured to send a protection switching requestmessage on a link protection tunnel of a link between the network nodeand a second node, and a node protection tunnel of the second noderespectively;

a receiving unit, configured to receive a protection switching responsemessage on the link protection tunnel of the link between the networknode and the second node, or the node protection tunnel of the secondnode; and

a switching unit, configured to switch services to the protection tunnelwhere the protection switching response message is received.

A ring network is provided, which includes:

a node 1, configured to detect a network fault, and send a ring networkprotection switching request message to a node 2, where the ring networkprotection switching request message carries source and destination nodeinformation of the ring network protection switching request message;and

a node 2, configured to determine a fault location according to thesource and destination node information, select a protection tunnelaccording to the determined fault location, and switch services to theselected protection tunnel, where the selected protection tunnel is alink protection tunnel of a link between the node 2 and the node 1, or anode protection tunnel of an intermediate node on a short way betweenthe node 2 and the node 1.

A ring network is further provided, which includes: a first node, asecond node and a third node, where the second node is adjacent to thefirst node and the third node respectively.

The first node is configured to select a protection tunnel according toa fault condition of a pre-established protection tunnel, switchservices to the selected protection tunnel, and send a protectionswitching request message on the selected protection tunnel, where theselected protection tunnel is a link protection tunnel of a link betweenthe first node and the second node or a node protection tunnel of thesecond node.

The second node is configured to switch the services to the linkprotection tunnel of the link between the first node and the second nodeif the protection switching request message is received on the linkprotection tunnel of the link between the first node and the secondnode.

The third node is configured to switch the services to the nodeprotection tunnel of the second node if the protection switching requestmessage is received on the node protection tunnel of the second node.

A ring network is also provided, which includes: a first node, a secondnode and a third node, where the second node is adjacent to the firstnode and the third node respectively.

The first node is configured to send a protection switching requestmessage respectively on a link protection tunnel of a link between thefirst node and the second node, and a node protection tunnel of thesecond node, receive a protection switching response message on the linkprotection tunnel of the link between the first node and the secondnode, or the node protection tunnel of the second node, and switchservices to the protection tunnel where the protection switchingresponse message is received.

The second node is configured to switch the services to the linkprotection tunnel of the link between the first node and the second nodeif the protection switching request message is received on the linkprotection tunnel of the link between the first node and the secondnode, and send the protection switching response message on the linkprotection tunnel of the link between the first node and the secondnode.

The third node is configured to switch the services to the nodeprotection tunnel of the second node, and send the protection switchingresponse message on the node protection tunnel of the second node, ifthe protection switching request message is received on the nodeprotection tunnel of the second node, and it is detected that a faultoccurs on a short way side between the end node and the first node.

In an embodiment of the present invention, after receiving a ringnetwork protection switching request message, a network node determinesfault location of a ring network according to the ring networkprotection switching request message, selects a protection tunnelaccording to the fault location of the ring network, and switchesservices to the selected protection tunnel, so as to ensure normalservice transmission.

In another embodiment of the present invention, a first node selects aprotection tunnel according to a fault state of a pre-establishedprotection tunnel, and sends a protection switching request message onthe selected protection tunnel, so that the other end of the protectiontunnel learns that services need to be switched to the protectiontunnel, so as to ensure normal service transmission.

In another embodiment of the present invention, a first node sends aprotection switching request message on two protection tunnels (a linkprotection tunnel of a link between a first node and a second node, anda node protection tunnel of the second node) respectively, and switchesservices to the protection tunnel where the protection switchingresponse message is received, so as to ensure normal servicetransmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a protection link in a mesh topologystructure in the prior art;

FIG. 2 is a schematic diagram of a protection tunnel according to anembodiment of the present invention;

FIG. 3 is a schematic diagram of a ring network protection methodaccording to Embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of a ring network protection methodaccording to Embodiment 3 of the present invention;

FIG. 5 is a schematic diagram of a ring network protection methodaccording to Embodiment 4 of the present invention;

FIG. 6 is an architecture diagram of a network node according toEmbodiment 13 of the present invention;

FIG. 7 is an architecture diagram of a network node according toEmbodiment 14 of the present invention; and

FIG. 8 is an architecture diagram of a network node according toEmbodiment 15 of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS Embodiment 1

Embodiment 1 of the present invention provides a ring network protectionmethod, which includes the following.

When a fault occurs in the ring network, a network node receives a ringnetwork protection switching request message sent by a node that detectsthe fault, where the ring network protection switching request messagecarries source and destination node information of the ring networkprotection switching request message.

A fault location is determined according to the source and destinationnode information, a protection tunnel is selected according to thedetermined fault location, and services are switched to the selectedprotection tunnel, where the selected protection tunnel is a linkprotection tunnel of a link between the network node and a source node,or a node protection tunnel of an intermediate node on a short waybetween the network node and the source node.

In Embodiment 1 of the present invention, after receiving the ringnetwork protection switching request message, the network nodedetermines the fault location of the ring network according to thereceived ring network protection switching request message, selects theprotection tunnel (the selected protection tunnel is the link protectiontunnel of the link between the network node and the source node, or thenode protection tunnel of the intermediate node on the short way betweenthe network node and the source node) according to the fault location ofthe ring network, and switches the services to the selected protectiontunnel to ensure normal service transmission.

In order to make Embodiment 1 of the present invention clearer, theprotection tunnel, that is, the node protection tunnel, ispre-established for each node in the ring network in Embodiment 1 of thepresent invention, and the protection tunnel, that is, the linkprotection tunnel, is established for each link between the adjacentnodes. It is assumed that n nodes exist on one ring, the number of theprotection tunnels established in the ring network is as follows: n nodeprotection tunnels+n link protection tunnels=2n protection tunnels. Asshown in FIG. 2, for example, it is assumed that 8 nodes A, B, C, D, E,F, G and H exist in the ring network altogether, 16 protection tunnelsare established altogether. In FIG. 2, the arc thick dotted linerepresents the link protection tunnel, and the arc thick solid linerepresents the node protection tunnel.

The node protection tunnels in Embodiment 1 and the subsequentembodiments have a long way.

Embodiment 2

Referring to FIG. 3, Embodiment 2 of the present invention provides aring network protection method, which is applicable to the protectionfrom a link fault. In the method, it is assumed that a fault occurs in aunidirectional link from a node A to a node B, and the node B detectsthe fault and sends a ring network protection switching request message.The method includes the following.

The node B reversely sends the ring network protection switching requestmessage in the ring network, where the message carries source nodeinformation and destination node information, that is, (B,A), and thesource and destination nodes are respectively the source and destinationnodes of the ring network protection switching request message, that is,the source node is the node B and the destination node is a nodeadjacent to the node B in a direction of detecting the fault at the nodeB, that is, the node A.

Other nodes in the ring network receive the ring network protectionswitching request message in sequence, judge whether the other nodes arethe destination nodes; if the other nodes are not the destination nodes,judge whether the other nodes detect the fault, and if the other nodesdo not detect the fault, transparently transmit the ring networkprotection switching request message to a next node. In this embodiment,the node B transparently transmits the ring network protection switchingrequest message to the node A through the nodes C, D, E, F, G and H.

After receiving the ring network protection switching request message,the node A determines that the node A is the destination node accordingto the destination node information in the message, learns the linkfault between the node A and the node B according to the topology of thering network, switches services to the link protection tunnel T1, andsends a ring network protection switching response message in the ringnetwork, where the ring network protection switching response messagecarries the source and destination node information (A,B).

After the node B receives the ring network protection switching responsemessage, the services are switched to the link protection tunnel T1.

In Embodiment 2 of the present invention, when a fault occurs in theunidirectional link from the node A to the node B, the node B sends thering network protection switching request message in a reverse directionof the ring network. After receiving the ring network protectionswitching request message, when determining that the node A is thedestination node, the node A switches the services to the linkprotection tunnel, so as to ensure normal service transmission.

Embodiment 3

Referring to FIG. 4, Embodiment 3 of the present invention provides aring network protection method, which is applicable to the protectionfrom a link fault. In the method, it is assumed that faults occur inbidirectional links between the node A and the node B, both the nodes Aand B detect the fault, and the nodes A and B respectively and reverselysend a ring network protection switching request message in the ringnetwork. The method specifically includes the following.

The node A and B reversely send the ring network protection switchingrequest message in the ring network. The ring network protectionswitching request message sent by the node A carries the source anddestination node information (A,B), and the ring network protectionswitching request message sent by the node B carries the source anddestination node information (B,A).

The node receiving the ring network protection switching request messagejudges whether the node is the destination node according to thedestination node information in the message; if the node is not thedestination node, judges whether the node detects the fault, and if thenode does not detect the fault, transparently transmits the ring networkprotection switching request message to a next node. In this embodiment,the ring network protection switching request message sent by the node Aand carrying the source and destination node information (A,B) istransparently transmitted to the node B through the nodes H, G, F, E, Dand C in sequence, and the ring network protection switching requestmessage sent by the node B and carrying the source and destination nodeinformation (B,A) is transparently transmitted to the node A through thenodes C, D, E, F, G and H in sequence.

The node B determines that the node B is the destination node accordingto the destination node information in the ring network protectionswitching request message, learns the link fault between the node A andthe node B according to the topology of the ring network, switchesservices to the link protection tunnel T1, and sends a ring networkprotection switching response message through the ring network, wherethe message carries the source and destination node information (B,A).The node A determines the node A is the destination node according tothe destination node information in the message, learns the link faultbetween the node A and the node B according to the topology of the ringnetwork, switches the services to the link protection tunnel T1, andsends the ring network protection switching response message through thering network, where the message carries the source and destination nodeinformation (A,B).

When the nodes A and B respectively receive the ring network protectionswitching response message, the protection switching is performed forboth, and no action is performed.

In Embodiment 3 of the present invention, when the fault occurs in thebidirectional links between the node A and the node B, the node B andthe node A respectively send the ring network protection switchingrequest message in the ring network. After receiving the ring networkprotection switching request message, when determining that the nodesare the destination nodes, the nodes A and B switch the services to thelink protection tunnel, so as to ensure normal service transmission.

Embodiment 4

Referring to FIG. 5, Embodiment 4 of the present invention provides aring network protection method, which is applicable to the protectionfrom a node fault. In the method, it is assumed that a fault occurs in anode B between a node A and a node C, both the nodes A and C detect thefault, and the nodes A and C respectively and reversely send a ringnetwork protection switching request message in the ring network. Themethod specifically includes the following.

The nodes A and C reversely send the ring network protection switchingrequest message in the ring network, the ring network protectionswitching request message sent by the node A carries the source anddestination node information (A,B), and the ring network protectionswitching request message sent by the node C carries the source anddestination node information (C,B).

The ring network protection switching request message sent by the node Aand carrying the source and destination node information (A,B) istransparently transmitted to the node C through the nodes H, G, F, E andD in sequence, and the ring network protection switching request messagesent by the node C and carrying the source and destination nodeinformation (C,B) is transparently transmitted to the node A through thenodes D, E, F, G and H in sequence.

The node C determines that the node C is not the destination nodeaccording to the destination node information in the ring networkprotection switching request message, detects a fault on a short wayside between the node C and the node B, determines that the fault occursin the node B according to the source and destination node informationand a network topology structure, switches services to a node protectiontunnel T3, and sends a protection switching response message through thering network, where the protection switching response message carriesthe source and destination node information (C,B). The node A determinesthat the node A is not the destination node according to the destinationnode information in the received ring network protection switchingrequest message, detects the fault on the short way side between thenode A and the node B, determines that the fault occurs on the node Baccording to the source and destination node information and the networktopology structure, switches the services to the node protection tunnelT3, and sends the protection switching response message through the ringnetwork, where the message carries the source and destination nodeinformation (A,B).

When the nodes A and C respectively receive the ring network protectionswitching response message, the protection switching is performed forboth, and no action is performed.

In Embodiment 4 of the present invention, when the fault occurs on thenode B between the node A and the node C, the node C and the node Arespectively send the ring network protection switching request messagein the ring network. After receiving the ring network protectionswitching request message, when determining that the nodes A and C arenot the destination nodes and both detecting the fault, the nodes A andC switch the services to the node protection tunnel, so as to ensurenormal service transmission.

In the foregoing embodiments of the present invention, when a faultoccurs in a ring network, after a node adjacent to the network faultdetects the fault, a corresponding link protection tunnel or nodeprotection tunnel is selected to perform protection switching through aring network protection switching mechanism. In the followingembodiments of the present invention, after the node adjacent to thenetwork fault detects the fault, the corresponding link protectiontunnel or node protection tunnel is selected to perform the protectionswitching through a linear protection switching mechanism.

The fault detection of the node adjacent to the network fault may beimplemented through an existing method in a fast reroute mechanism (forexample, a link layer protocol, a hello mechanism in a ResourceReservation Protocol (RSVP)) defined in the Internet Engineering TaskForce (IETF), or may be implemented through a fault detection method ofOperation, administration and maintenance (OAM) defined according toInternational Telecommunication Union-Telecommunication StandardizationSector (ITU-T), which is not described in detail here.

Embodiment 5

Embodiment 5 of the present invention provides a ring network protectionmethod, which includes the following.

A first node selects a protection tunnel according to a fault conditionof a pre-established protection tunnel, switches services to theselected protection tunnel, sends a protection switching request messageon the selected protection tunnel, and informs another end node of theselected protection tunnel to switch the services to the selectedprotection tunnel.

A manner of sending the protection switching request message on theselected protection tunnel includes, but is not limited to, thefollowing manner: sending an OAM packet, and a format of the OMA packetis as shown in Table 1:

TABLE 1 Tunnel Label LSP Label OAM PDU

Tunnel Label is a label of the selected protection tunnel, and OAM PDUincludes the protection switching request message. Specifically, anintermediate node on the protection tunnel forwards the OAM packet to anext node, and the other end node of the protection tunnel determines,according to the protection switching request message in the OAM packet,to switch the services to the protection tunnel.

In Embodiment 5 of the present invention, the first node selects theprotection tunnel for service switching according to the fault conditionof the pre-established protection tunnel, switches the services to theselected tunnel, and sends the protection switching request message onthe selected protection tunnel so that the other end of the protectiontunnel learns that the services need to be switched to the protectiontunnel, so as to ensure normal service transmission.

The first node may be the node B in following Embodiment 6, or the nodeA or the node B in following Embodiment 7, or the node A or the node Cin following Embodiment 8.

Embodiment 6

Referring to FIG. 2, Embodiment 6 of the present invention provides aring network protection method. In the method, it is assumed that a linkfault occurs between a node A and a node B, the node B detects thefault, and in the method, the mode B sends a protection switchingrequest message on a protection link. The method includes the following.

The node B detects whether a fault occurs in a link protection tunnel,and if the fault does not occur, selects a link protection tunnel T1 asthe protection tunnel of the current service transmission, switchesservices to the link protection tunnel T1, and sends the protectionswitching request message on the link protection tunnel T1.

An intermediate node on the link protection tunnel T1 receives theprotection switching request message, and forwards the protectionswitching request message to a next node in the same processing manneras the processing manner after receiving a common data packet or acontrol protocol.

The node A (the other end node of the link protection tunnel T1)receives the protection switching request message, switches the servicesto the link protection tunnel T1, and sends a protection switchingresponse message on the link protection tunnel T1. When the node Breceives the protection switching response message, the link protectionswitching is implemented, and no action is performed.

In Embodiment 6 of the present invention, when the fault occurs in aunidirectional link from the node A to the node B, the services areswitched to the link protection tunnel, and the protection switchingrequest message is sent on the link protection tunnel so that the otherend of the link protection tunnel learns that the services need to beswitched to the link protection tunnel, so as to ensure normal servicetransmission.

Embodiment 7

Referring to FIG. 2, Embodiment 7 of the present invention provides aring network protection method. In the method, it is assumed that faultsoccur in bidirectional links between a node A and a node B, both thenode A and the node B detect the faults in the ring network, and thenodes A and B respectively send a protection switching request messageon a link protection link. The method includes the following.

The node B does not detect the fault on the link protection tunnel,selects a link protection tunnel T1 as the protection tunnel of thecurrent service transmission, switches services to the link protectiontunnel T1, and sends the protection switching request message on thelink protection tunnel T1. The node A does not detect the fault on thelink protection tunnel, selects the link protection tunnel T1 as theprotection tunnel of the current service transmission, switches theservices to the link protection tunnel T1, and sends the protectionswitching request message on the link protection tunnel T1.

When the node A and the node B respectively receive the protectionswitching request message sent by each other (the node B and the node A)on the link protection tunnel T1, the link protection switching isperformed for both, and no action is performed, and then a protectionswitching response message is sent on the link protection tunnel.

When the node A and the node B respectively receive the protectionswitching response message sent by each other (the node B and the nodeA) on the link protection tunnel T1, no action is performed.

In Embodiment 7 of the present invention, when the faults occur in thebidirectional links between the node A and the node B, the node A andthe node B respectively switch the services to the link protectiontunnel, and send the protection switching request message on the linkprotection tunnel so that the other end of the link protection tunnelknows that the services need to be switched to the link protectiontunnel, so as to ensure normal service transmission.

Embodiment 8

Referring to FIG. 2, Embodiment 8 of the present invention provides aring network protection method. It is assumed that a fault occurs in anode B in the method, a node A and a node C detect the fault and, andrespectively send a protection switching request message on a nodeprotection link in the method, the method includes the following.

The node A detects the fault on a link protection tunnel T1, detectsthat no fault occurs in a node protection tunnel T3, selects the nodeprotection tunnel T3 to perform protection switching, and sends theprotection switching request message on the node protection tunnel T3.The node C detects the fault on a link protection tunnel T2, detectsthat no fault occurs in the node protection tunnel T3, selects the nodeprotection tunnel T3 to perform the protection switching, and sends theprotection switching request message on the node protection tunnel T3.

When the node A and the node C respectively receive the protectionswitching request message sent by each other (the node C and the node A)on the node protection tunnel T3, the node protection switching isperformed for both, and no action is performed, and then the node A andthe node C respectively send a protection switching response message onthe node protection tunnel T3.

When the node A and the node C respectively receive the protectionswitching response message sent by each other (the node C and the nodeA) on the node protection tunnel T3, no action is performed.

In Embodiment 8 of the present invention, when the fault occurs in thenode B, the node A and the node C respectively switch services to thenode protection tunnel, and send the protection switching requestmessage on the node protection tunnel so that the other end of the nodeprotection tunnel knows that the services need to be switched to thelink protection tunnel, so as to ensure normal service transmission.

Embodiment 9

Embodiment 9 of the present invention provides a ring network protectionmethod, where the method includes the following.

A first node sends a protection switching request message on a linkprotection tunnel of a link between the first node and a second node,and a node protection tunnel of the second node respectively.

A protection switching response message is received on the linkprotection tunnel of the link between the first node and the secondnode, or the node protection tunnel of the second node.

Services are switched to the protection tunnel where the protectionswitching response message is received.

A manner of sending the protection switching request message on theprotection tunnel includes, but is not limited to, the following manner:sending an OAM packet on the protection tunnel.

The first node may be the node A in the following embodiments, thesecond node may be the node B in the following embodiments, and thethird node may be the node C in the following embodiments.

In Embodiment 9 of the present invention, the first node sends theprotection switching request message on the link protection tunnel andthe node protection tunnel respectively, and switches the services tothe protection tunnel where the protection switching response message isreceived, so as to ensure normal service transmission.

Embodiment 10

Referring to FIG. 2, Embodiment 10 of the present invention provides aring network protection method. In the method, it is assumed that afault occurs in a unidirectional link from a node A to a node B, and thenode B detects the fault and sends a protection switching requestmessage on both a link protection tunnel and a node protection tunnel.The method includes the following.

The node B sends the protection switching request message on a linkprotection tunnel T1 and a node protection tunnel T4.

An intermediate node on the link protection tunnel T1 and the nodeprotection tunnel T4 receives the protection switching request message,and forwards the protection switching request message to a next node inthe same processing manner as the processing manner after receiving acommon data packet or a control protocol.

A node H receives the protection switching request message on the nodeprotection tunnel T4, and detects that no fault occurs in the networkfrom the node H to the node A, and no action is performed.

The node A receives the protection switching request message on the linkprotection tunnel T1, selects the link protection tunnel T1 to performprotection switching, and sends a protection switching response messagethrough the link protection tunnel T1.

The node B receives the protection switching response message sent bythe node A on the link protection tunnel T1, and selects the linkprotection tunnel T1 to perform the protection switching.

In Embodiment 10 of the present invention, when the fault occurs in theunidirectional link from the node A to the node B, the node B sends theprotection switching request message respectively on the link protectiontunnel and the node protection tunnel, and the node A receives theprotection switching request message on the link protection tunnel, andthen switches services to the link protection tunnel, so as to ensurenormal service transmission.

Embodiment 11

Referring to FIG. 2, Embodiment 11 of the present invention provides aring network protection method. It is assumed that faults occur inbidirectional links between a node A and a node B, and the node A andthe node B respectively send a protection switching request message onboth a link protection tunnel and a node protection tunnel. The methodspecifically includes the following.

The node A sends the protection switching request message on a linkprotection tunnel T1, and meanwhile sends the protection switchingrequest message on a node protection tunnel T3. The node B sends theprotection switching request message on the link protection tunnel T1,and meanwhile sends the protection switching request message on a nodeprotection tunnel T4.

The node A and the node B respectively receive the protection switchingrequest message sent by each other (the node B and the node A) on thelink protection tunnel T1, select the link protection tunnel T1 toperform the link protection switching, and send the protection switchingrequest message through the link protection tunnel T1.

A node C and a node H respectively receive the protection switchingrequest messages sent by the node A and the node B on the nodeprotection tunnels T3 and T4, but no fault is locally detected on theB-C or A-H side, and therefore no action is performed.

When the node A and the node B respectively receive a protectionswitching response message sent by each other (the node B and the nodeA) on the link protection tunnel T1, the link protection switching isperformed for both, and no action is performed.

In Embodiment 11 of the present invention, when the faults occur in thebidirectional links between the node A and the node B, both the node Aand the node B send the protection switching request messagerespectively on the link protection tunnel and the node protectiontunnel, and an opposite end node (the node B and the node A) of the linkprotection tunnel receives the protection switching request message onthe link protection tunnel and then switches services to the linkprotection tunnel, so as to ensure normal service transmission.

Embodiment 12

Referring to FIG. 2, Embodiment 12 of the present invention provides aring network protection method. It is assumed that a fault occurs in anode B in the method, a node A and a node C detect the fault and both anode A and a node C detect the fault and send a protection switchingrequest message respectively on a link protection tunnel and a nodeprotection link. The method specifically includes the following.

The node A sends the protection switching request message on a linkprotection tunnel T1, and meanwhile sends the protection switchingrequest message on a node protection tunnel T3. The node C sends theprotection switching request message on a link protection tunnel T2, andmeanwhile sends the protection switching request message on the nodeprotection tunnel T3.

The node A and the node C respectively receive the protection switchingrequest message sent by each other (the node C and the node A) on thenode protection tunnel T3, detect the fault on the A-B or the C-B sidelocally, and then select the node protection tunnel T3 to perform thelink protection switching on the current side, and send a protectionswitching response message through the node protection tunnel T3.

When the node A and the node C respectively receive the protectionswitching response message sent by each other (the node C and the nodeA) on the node protection tunnel T3, the node protection switching isperformed for both, and no action is performed.

In Embodiment 12 of the present invention, when the fault occurs in thenode B between the node A and the node C, the node A and the node C sendthe protection switching request message respectively on the linkprotection tunnel and the node protection tunnel, and an opposite endnode (the node C and the node A) of the node protection tunnel receivesthe protection switching request message on the node protection tunnel,and then switches services to the node protection tunnel, so as toensure normal service transmission.

It should be noted that, the protection switching request message andthe protection switching response message in Embodiment 12 of thepresent invention may but is not limited to use an OAM packet of adigital plane, and a protocol packet of a control plane or other packetsmay also be used, which does not affect the implementation of thepresent invention.

Embodiment 13

Referring to FIG. 6, Embodiment 13 of the present invention provides anetwork node, which includes:

a receiving unit 601, configured to receive a ring network protectionswitching request message, where the ring network protection switchingrequest message carries source and destination node information of thering network protection switching request message;

a protection tunnel selection unit 602, configured to determine a faultlocation of the ring network according to the source and destinationnode information, and select a protection tunnel according to thedetermined fault location of the ring network, where the selectedprotection tunnel is a link protection tunnel of a link between thesource node and the network node, or a node protection tunnel of anintermediate node on a short way between the source node and the networknode; and

a switching unit 603, configured to switch services to the selectedprotection tunnel.

Specifically, the protection tunnel selection unit 602 is configured todetermine a link fault between the network node and the source node whenthe network node is the destination node; select the link protectiontunnel between the network node and the source node; determine a faultof the intermediate node on the short way between the network node andthe source node, when the network node is not the destination node andit is detected that a fault occurs on the short way side between thenetwork node and the source node; and select the node protection tunnelof the intermediate node.

The network node further includes: a tunnel establishment unit 604,configured to establish the link protection tunnel of the link betweenthe source node and the network node, or establish the node protectiontunnel of the intermediate node on the short way between the source nodeand the network node.

In Embodiment 13 of the present invention, after receiving the ringnetwork protection switching request message, the network nodedetermines the fault location of the ring network according to thereceived protection switching request message, selects the protectiontunnel (the selected protection tunnel is the link protection tunnel ofthe link between the network node and the source node, or the nodeprotection tunnel of the intermediate node on the short way between thenetwork node and the source node) according to the fault location of thering network, and switches the services to the selected protectiontunnel to ensure normal service transmission.

Embodiment 14

Referring to FIG. 7, Embodiment 14 of the present invention provides anetwork node, which includes:

a selection unit 701, configured to select a protection tunnel accordingto a fault condition of a pre-established protection tunnel;

a switching unit 702, configured to switch services to the selectedprotection tunnel; and

a sending unit 703, configured to send a protection switching requestmessage on the selected protection tunnel.

Specifically, the selection unit 701 is configured to detect whether afault occurs in the link protection tunnel of a link between the networknode and a second node; if the fault does not occur, select the linkprotection tunnel of the link between the network node and the secondnode, and if the fault occurs, and no fault occurs in the nodeprotection tunnel of the second node, select the node protection tunnelof the second node.

The network node further includes:

a tunnel establishment unit 704, configured to establish the linkprotection tunnel of the link between the network node and the secondnode, or establish the node protection tunnel of the second node.

In Embodiment 14 of the present invention, the network node selects theprotection tunnel according to a fault state of the pre-establishedprotection tunnel, and sends the protection switching request message onthe selected protection tunnel so that the other end of the protectiontunnel learns that the services need to be switched to the protectiontunnel, so as to ensure normal service transmission.

Embodiment 15

Referring to FIG. 8, Embodiment 15 of the present invention provides anetwork node, which includes:

a sending unit 801, configured to send a protection switching requestmessage on a link protection tunnel of a link between the network nodeand a second node, and a node protection tunnel of the second noderespectively:

a receiving unit 802, configured to receive a protection switchingresponse message on the link protection tunnel of the link between thenetwork node and the second node, or the node protection tunnel of thesecond node: and

a switching unit 803, configured to switch services to the protectiontunnel where the protection switching response message is received.

The network node further includes: a tunnel establishment unit 804,configured to establish the link protection tunnel of the link betweenthe network node and the second node, or establish the node protectiontunnel of the second node.

In Embodiment 15 of the present invention, the network node sends theprotection switching request message respectively on two protectiontunnels, and switches the services to the protection tunnel where theprotection switching response message is received, so as to ensurenormal service transmission.

Embodiment 16

Embodiment 16 of the present invention provides a ring network, whichincludes:

a node 1, configured to detect a network fault, and send a ring networkprotection switching request message to a node 2, where the protectionswitching request message carries source and destination nodeinformation of the ring network protection switching request message;and

a node 2, configured to determine a fault location of the ring networkaccording to the source and destination node information, select aprotection tunnel according to the determined fault location of the ringnetwork, and switch services to the selected protection tunnel, wherethe selected protection tunnel is a link protection tunnel of a linkbetween the node 2 and the node 1, or a node protection tunnel of anintermediate node on a short way between the node 2 and the node 1.

In Embodiment 16 of the present invention, after the node 2 in the ringnetwork receives the ring network protection switching request message,the node 2 determines the fault location of the ring network accordingto the ring network protection switching request message, selects theprotection tunnel according to the fault location of the ring network,and switches the services to the selected protection tunnel, so as toensure normal service transmission.

Embodiment 17

Embodiment 17 of the present invention provides a ring network, whichincludes: a first node, a second node and a third node, where the secondnode is adjacent to the first node and the third node respectively.

The first node is configured to select a protection tunnel according toa fault condition of a pre-established protection tunnel, switchservices to the selected protection tunnel, and send a protectionswitching request message on the selected protection tunnel, where theselected protection tunnel is a link protection tunnel of a link betweenthe first node and the second node or a node protection tunnel of thesecond node.

The second node is configured to switch the services to the linkprotection tunnel of the link between the first node and the second nodeif the protection switching request message is received on the linkprotection tunnel of the link between the first node and the secondnode.

The third node is configured to switch the services to the nodeprotection tunnel of the second node if the protection switching requestmessage is received on the node protection tunnel of the second node.

In Embodiment 17 of the present invention, the first node in the ringnetwork selects the protection tunnel according to a fault state of thepre-established protection tunnel, and sends the protection switchingrequest message on the selected protection tunnel so that the other endof the protection tunnel learns that the services need to be switched tothe protection tunnel, so as to ensure normal service transmission.

Embodiment 18

Embodiment 18 of the present invention provides a ring network, whichincludes: a first node, a second node and a third node, where the secondnode is adjacent to the first node and the third node respectively.

The first node is configured to send a protection switching requestmessage respectively on a link protection tunnel of a link between thefirst node and the second node, and a node protection tunnel of thesecond node; receive a protection switching response message on the linkprotection tunnel of the link between the first node and the secondnode, or the node protection tunnel of the second node; and switchservices to the protection tunnel where the protection switchingresponse message is received.

The second node is configured to switch the services to the linkprotection tunnel of the link between the first node and the secondnode, and send the protection switching response message on the linkprotection tunnel of the link between the first node and the secondnode, if the protection switching request message is received on thelink protection tunnel of the link between the first node and the secondnode.

The third node is configured to switch the services to the nodeprotection tunnel of the second node, and send the protection switchingresponse message on the node protection tunnel of the second node, ifthe protection switching request message is received on the nodeprotection tunnel of the second node and it is detected that a faultoccurs on a short way side between the end node and the first node.

In Embodiment 18 of the present invention, the first node in the ringnetwork sends the protection switching request message respectively ontwo protection tunnels, and switches the services to the protectiontunnel where the protection switching response message, so as to ensurenormal service transmission is received.

Those of ordinary skill in the art should understand that all or a partof the steps of the method according to the embodiments of the presentinvention may be implemented by means that a program instructs relevanthardware. The program may be stored in a computer readable storagemedium, for example, a read-only memory (ROM), a magnetic disk or anoptical disk.

The ring network protection method, the network node and the ringnetwork are described in detail above through the embodiments of thepresent invention. The principle and implementation of the presentinvention are described herein through specific examples. Thedescription of the embodiments of the present invention is merelyprovided for easy understanding of the method and core ideas of thepresent invention. Persons of ordinary skill in the art can makevariations and modifications to the present invention in terms of thespecific implementations and application scopes according to the ideasof the present invention. Therefore, the specification shall not beconstrued as a limit to the present invention.

What is claimed is:
 1. A ring network protection method, wherein thering network comprises a plurality of nodes and any two adjacent nodesare connected by a link, the method comprising: receiving, by a node, aring network protection switching request when a fault occurs in thering network, wherein the ring network protection switching requestcarries information of a source node and a destination node of the ringnetwork protection switching request; determining, by the node, a faultlocation according to the information of the source node and thedestination node, and selecting a protection tunnel according to thedetermined fault location; and switching, by the node, services to theselected protection tunnel, wherein if the node is the destination node,and the fault is located in a link between the node and the source node,a link protection tunnel is selected as the protection tunnel for thelink between the node and the source node; and if the node is not thedestination node, and the fault is located at the destination node whichis on a short way side between the node and the source node, a nodeprotection tunnel is selected as the protection tunnel for thedestination node.
 2. The method according to claim 1, furthercomprising: for each node in the ring network, establishing a nodeprotection tunnel for the node, wherein the node protection tunnelconnects two nodes adjacent to the node; and for each link in the ringnetwork, establishing a link protection tunnel for the link, wherein thelink protection tunnel connects two end nodes of the link.
 3. A node,located in a ring network, wherein the ring network comprises aplurality of nodes and any two adjacent nodes are connected by a link,the node comprising: a receiving unit, configured to receive a ringnetwork protection switching request when a fault occurs in the ringnetwork, wherein the ring network protection switching request carriesinformation of a source node and a destination node of the ring networkprotection switching request; a protection tunnel selection unit,configured to determine a fault location according to the information ofthe source node and the destination node, and select a protection tunnelaccording to the determined fault location; wherein the selectedprotection tunnel is a link protection tunnel of a link between a sourcenode and the node, if the fault location is between the node and thesource node and the node is the destination node; or the selectedprotection tunnel is a node protection tunnel of the destination node ona short way between the source node and the node, if the fault locationis on the destination node and the node is not the destination node; anda switching unit, configured to switch services to the selectedprotection tunnel.
 4. The node according to claim 3, further comprising:a tunnel establishment unit, configured to: establish a link protectiontunnel for each link in the ring network, wherein the link protectiontunnel connects two end nodes of the link, and establish a nodeprotection tunnel for each node in the ring network, wherein the nodeprotection tunnel connects two nodes adjacent to the node.
 5. A ringnetwork, comprising a plurality of nodes, any two adjacent nodes beingconnected by a link, wherein: a first node is configured to detect afault in the ring network, and send a ring network protection switchingrequest to a second node, wherein the ring network protection switchingrequest carries information of a source node and a destination node ofthe ring network protection switching request; and the second node isconfigured to receive the ring network protection switching request,determine a fault location according to the information of the sourceand the destination node, select a protection tunnel according to thedetermined fault location, and switch services to the selectedprotection tunnel, wherein the selected protection tunnel is a linkprotection tunnel of a link between the second node and the first node,if the fault location is between the first node and the second node andthe second node is the destination node; or the selected protectiontunnel is a node protection tunnel of the destination node on a shortway between the second node and the first node, if the fault location ison the destination node and the second node is not the destination node.